Evaluate the definite integral. $\int^{10}_{9}-6\,dx = $
First, use the power rule: $\int^{10}_{9}-6\,dx ~=~-6x\Bigg|^{10}_{9}$ Second, plug in the limits of integration and simplify: $[-6\cdot{10}]-[-6\cdot{9}] = -60+54 = -6$. The answer: $\int^{10}_{9}-6\,dx ~=~ -6$